1. Field
The present application relates to a surface inspection apparatus executing a defect inspection of repetitive patterns formed on a surface of a suspected substance.
2. Description of the Related Art
There is known an apparatus which irradiates illumination light for inspection to repetitive patterns formed on a surface of a suspected substance (semiconductor wafer, liquid crystal substrate and the like, for instance), and executes a defect inspection of the repetitive patterns based on light generated from the repetitive patterns at this time. There are various methods applied to this inspection apparatus in accordance with a type of light (for instance, diffraction ray, scattered light, regular reflection light, and the like) generated from the repetitive patterns. Further, regarding the illumination light for inspection to be used, an apparatus using unpolarized light, an apparatus using linearly polarized light (refer to Patent Document 1: International Publication Pamphlet WO 2005/040776, for instance), and the like are known. Each of these inspection apparatus can collectively detect defects of the repetitive patterns in a relatively wide area (whole area, for instance) on the surface of the suspected substance, and can execute a defect inspection in a high throughput manner.
However, there are various types of defects of repetitive patterns. For example, as a typical type of defect generated at a time of an exposure on a suspected substance, a defocus defect and a dose defect can be cited. Under the present situation, it is difficult to separately detect the various types of defects in the aforementioned apparatus, so that a plurality of types of defects are collectively detected. However, as a result of repeated studies by the present inventors, it has been found that a detection sensitivity to the defect largely depends on a combination of the type and a detection method of the defect, and with a certain specific detection method, sufficient detection sensitivity cannot be obtained depending on the type of the defect. Further, it also has been found that even a defect in which sufficient detection sensitivity thereto cannot be obtained with a certain detection method can be detected in a highly sensitive manner by using another detection method.